1. Technical Field
The present disclosure relates to an optical device and a projector provided with the optical device.
2. Related Art
In the related art, a projector provided with a so-called three-plate optical device that separates a light flux emitted from a light source into red, green and blue color lights, that is, three primary colors by a color separating optical system using a dichroic mirror or the like, modulates each color light according to the image information by three liquid crystal panels (a light modulating device), combines the respective color lights after image modulation with a cross dichroic prism (a color combining optical device), and projects a color image in an enlarged scale via a projecting lens is known.
In the optical device as described above, assembleability is improved by assembling an optical element such as a liquid crystal panel or a polarizing plate integrally to a cross dichroic prism.
An example of the assembled structure of the optical device will be described (for example, see JP-A-2003-121931). The assembled structure in the above-described document includes a fixed member being fixed to a light flux incoming end surface of the cross dichroic prism having a plurality of pins projecting toward the light flux incoming side, a holding frame storing a liquid crystal panel in a frame, and a supporting member being mounted to the holding frame via the liquid crystal panel and holding the liquid crystal panel in cooperation with the holding frame therebetween. The liquid crystal panel is arranged so as to face the light flux incoming end surface of the cross dichroic prism by the pins of the fixed member being inserted into holes formed on a frame portion of the holding frame.
The liquid crystal panel is fixed to the fixed member by bonding the holes of the holding frame to the pins of the fixed member at an adequate focus alignment position with respect to the light flux incoming end surface of the cross dichroic prism.
When the projector is operated, heat is generated in the liquid crystal panel by transmission of the light flux, driving by electric signals, and so on. This heat may cause deterioration of the liquid crystal panel and hence deterioration of the image quality of a projected image. Therefore, it is necessary to be cooled efficiently as much as possible.
In the optical device disclosed in JP-A-2003-121931, since the liquid crystal panel is fixed to the fixed member by bonding between a side surface of the pin and an inner surface of the hole, displacement of the respective members at a bonding surface may occur due to vibrations or heat. In this case, displacement of the projecting lens of the liquid crystal panel from a back-focus position or displacement of pixel between the respective liquid crystal panels may result in deterioration of the image quality of the projected image.